1. Field of the Invention
The present invention relates to a digital camera, and more particularly to a digital camera for recording, in storage memory as image data for storage purpose (hereinafter called “storage image data”), image data—preceding, by a predetermined time lag period, image data acquired at the time of receipt of a capture instruction—among a plurality of items of image data consecutively output by an image sensor until the photographing command is received.
2. Related Art
When the user has perceived a moment, which the user desires to photograph, and has depressed a shutter switch of a camera, a time lag arises from when an object is actually, visually perceived until the shutter button is depressed, and another time lag corresponding to the amount of time required by the camera to capture an image also occurs. There may arise a case where an image of the moment, which the user has desired to photograph, cannot be recorded, because of these time lags.
For these reasons, Japanese Patent Laid-Open Publication 2002-271673 describes the following digital camera. The digital camera is provided with a time lag measurement mode, and a time (time lag) T1—from when the user has made visual perception until when the shutter switch is depressed—has been measured in advance. When having completed preparations for photographing, such as AE (Automatic Exposure)/AF (Automatic Focus) processing, the digital camera starts capturing image data without awaiting depression of the shutter switch. The digital camera sequentially stores the thus-captured image data into memory for temporary recording purpose, thereby retaining image data for at least a period of T1. When the user has depressed the shutter switch, the digital camera selects the image data, which go back only a time T1 from when the shutter switch is depressed, as image data for storage purpose. The thus-selected image data are stored in recording memory. The digital camera illuminates an LED, thereby measuring a time which elapses before depression of the shutter switch. Thus, the time lag is measured.
However, the time lag varies depending on a state of the user's mind or according to the type of a subject. Therefore, even when the image data, which go back a previously-measured time lag, have been selected, the image data are not always desired image data for the user.
The present invention provides a digital camera which lessens the influence of a time lag and which enables recording of image data at desired photographing timing.